Funnily enough I was up in Stornoway on Monday with work and chatting to the lads up there and studying a few charts I was planning on doing a week camping, fishing and a bit of sheltered canoeing(I'm a bit of a newbie there) in May. The plan is to take my vehicle so I can bring the canoe, ferry to Barra, ferry to Uist, Ferry to Harris and eventually ferry to Ullapool. Chatting to the guys I know over there wild camping shouldn't be a problem. May has in the last few years been better for weather and there shouldn't be that many tourists. If I manage to pull it off I'll put a bit up on here with photo's.
May is the best time to visit Scotland IMO. I was up there for the last week in May last year, and the first week of June. The blighters were early too. You should be just before the midges and enjoy the least rainfall. That, or wait to mid-September!
If you go after that, take midge nets. They do take the worst off the experience. Scottish midges are b*****ds.
Most of the trees are in the Castle grounds in Stornoway. This is open to the public but as far as I know camping is not allowed. There are smaller plantations (but not many) dotted around the island. They are mostly conifers.
The sheer ferocity of the wind causes the trees to suffer from wind burn so it is very hard for them to get a foothold.
I have camped many times on the moors of Lewis, in the mountains of Harris and on the coast. There are plenty of places to wild camp if you keep a low profile. I have hammocked in some places but brought some of my larger climbing slings to wrap around stony outcrops to do this. Can be done with a bit if thought. Bring a tent to be safe though or at least a bivi bag and tarp.
If you camp on the coast there should be plenty of driftwood to make a small fire. Inland there is little in the way of wood to scavenge. If you speak to a crofter and you get permission to camp locally see if you can blag some peat from them as that is what is used in the rural areas for fires.
No idea about the first one but trees are few and far between up there.
The second one is of the Scalpay Bridge I think. It used to be a ferry that went across here everyday except a Sunday. A short but choppy trip.
The third picture is of an inlet called Stoth (pronounced Sto). We spent many a Sunday in the summer here as the churchgoers did not appear here to tut at you. Just of to the left near the building there is a little road on a steep slope. When learning to drive my fathers car on my own I could not get the hang of the clutch one time and it kept rolling backwards to the cliff. Got it just in time as it hit the grass. Nearby is the lighthouse where my father was a part time keeper. My first job was to assist him there as he would be so knackered working during the day (as a brickie) so I would go along with him on his night shift. This involved winding the light up every 45 minutes and taking weather readings mainly.
The fourth is the Whalebone arch at Bragar on the west coast. The bones are from the lower jaw of a Blue whale. It was found dead on the beach there in the early 20's with the harpoon 9centre of arch) still in its head. Seemingly the harpoon had a charge in it that had failed to explode hence the intact bones.
The last picture looks like it was taken in Lochs or Harris.